Herbicide Rate Calculator

Work out herbicide rate instantly with clear inputs, formula shown and shareable results.

About Herbicide Rate Calculator

Herbicide recommendations from trials are given as grams of active ingredient per hectare, but the product on the shelf is a formulation of stated strength. Product rate = a.i. rate / concentration, so 1000 g a.i./ha of a 480 g/L glyphosate is 2.08 litres per hectare.

Formula

Product from active ingredient

Product (L or kg per ha) = a.i. rate (g/ha) / concentration (g per L or kg)

Worked example

With the default values below, Herbicide Rate Calculator returns Product Rate of 2.083. Change any input above and every figure here is recalculated in your browser.

Inputs used

Active Ingredient Rateminimum 0.1 g a.i./ha: 1,000 g a.i./ha
Product Concentrationminimum 0.1 g a.i. per L or kg: 480 g a.i. per L or kg
Area To Treatminimum 0.01 ha: 5 ha
Product Priceminimum 0 per L or kg: 450 per L or kg

Results

Product Rate: 2.083
Total Product Required: 10.417
Total Herbicide Cost: $4,687.50
Total Active Ingredient: 5.000

Step by step

1Values used
2Product from active ingredient
3Product Rate= 2.083
4Total Product Required= 10.417
5Total Herbicide Cost= 4,687.50
6Total Active Ingredient= 5.000

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Herbicides are regulated products. Do not exceed the maximum label rate, respect rotational crop restrictions and buffer zones, and record every application.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Herbicides are regulated products. Do not exceed the maximum label rate, respect rotational crop restrictions and buffer zones, and record every application.

Frequently Asked Questions

Why work from active ingredient rather than the product rate?

Products of the same chemistry come in many strengths — glyphosate alone is sold at 360, 480 and 540 g/L. Working from a.i. lets you switch products without changing the agronomy.

Should I add a surfactant?

Only if the label calls for one. Many formulations already contain adjuvant; adding more can cause phytotoxicity or reduce rainfastness.